Filter assembly

ABSTRACT

Apparatuses and methods for making and using a filter cloth assembly are described. A filter cloth assembly can have a liquid permeable filtering media attached to a connector ring. The liquid permeable filtering media separates at least one solid from at least one liquid in a slurry. The filtering media has a feed hole formed therein to allows passage of a slurry through the filtering media. The connector ring includes a flange having an upper flange section and a lower flange section. The lower flange section receives an edge of the feed hole to connect the filtering media to the connector ring such that the face of the filtering media is substantially flush with the upper flange section.

RELATED APPLICATIONS

The present application claims priority as a continuation-in-part toU.S. patent application Ser. No. 11/274,823, entitled “FILTER CLOTHCONNECTOR”, filed Nov. 14, 2005, which in turn claims priority to U.S.patent application Ser. No. 10/676,322, entitled “FILTER CLOTHCONNECTION”, filed Sep. 30, 2003, which in turn claims priority to U.S.Provisional Patent Application Ser. No. 60/414,718, entitled “Method ofAssembling a Filter Plate”, filed Sep. 30, 2002, the entire contents ofboth of which are herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a filter plate in a filter press forseparating solids and liquids. More particularly, the present inventionrelates to a system and method for attaching a filter media to a filterplate.

BACKGROUND OF THE INVENTION

A filter press is an economic and efficient liquid/solid separationdevice commonly utilized in the clay, chemical, or mining industries.Filter presses generally employ a plurality of filter plates, eachfilter plate having large areas of a textile material to form afiltering screen. The textile material is typically attached to a cloth,rubber or plastic tubular hub. The tubular hub allows the material to befiltered to pass through successive filtering chambers in the press. Thetubular hub must be securely attached to the filtering material toprevent leakage, and is usually constructed of a textile tube or athermoplastic or rubber material.

In the current state of the art, filter cloth is generally installed onthe filter plates by rolling up one side of a duplex filter cloth, whichis joined at a feed hole with the tubular hub, and then pushing therolled up filter cloth through the feed hole of the filter plate. Afterpassing the rolled cloth through the feed hole, the filter cloth is thenunrolled. The filter plate thus has a layer of filter cloth on eitherside thereof, and the two filter cloth layers are fastened together onthe filter plate. Slurry is pumped into the filter press and fills eachcavity within the stack of filter plates. Solids remain in the chambersand filtrate passes through the cloth, exiting the filter plate.

Conventional methods for joining the filtering material to the tubularhub include sewing the two filter cloth layers together. This approachis labor intensive and thus expensive. Moreover, the sewing tends tocreate weaknesses in the joint due to the stitch holes. Stitching canalso be difficult due to the thickness of the filter cloth and thetubular hub. Other methods include adhesive and bonding agents to securethe filtering cloth to the tubular hub, but these techniques are timeconsuming since the adhesive must set to form the bond, and is notconsistently reliable. Welding requires a split clamping collarpositioned between the flanges of the feed neck to transmit force to theweld from a clamping cylinder.

U.S. Pat. No. 4,765,859 describes a method of joining filter cloth to arubber tubular hub for use as a filter screen, which is installed on afiltering plate in a filtering press. The hub consists of a cylindricaltube that includes two annular flanges protruding radially outward fromthe circumference of the tube at each end. The tubular hub is fabricatedfrom a rubber material that is collapsible. A filtering screen is thenconstructed by joining two filter cloths to the hub at each end of thetube. One filter cloth is joined to the hub at the inside surface of oneflange, while the other filter cloth is joined to the inside surface ofthe other flange. The filter cloth and hub are bonded together byinduction heating to form a seal to prevent leakage of the filteredmaterial.

U.S. Pat. No. 5,958,173, the contents of which are herein incorporatedby reference, describes a method of fabricating a filter screen for afilter press by attaching a filter cloth to a tubular hub usinginduction heating.

The methods in the prior art of attaching a filter cloth to a filterplate pose a number of disadvantages. The prior methods of installingfilter cloths are difficult and time consuming, particularly for largerfilters (up to 2 meters by 2 meters square). The large cloth requires aperson on each side of the filter plate: one person to push the filtercloth through the hole, and the other person to receive the filtercloth. Large presses are usually re-clothed without removing plates,requiring operators to get between the plates physically, sometimes onplatforms above conveyors or high above the ground level, a procedurethat can be dangerous. The removal of filter plates in order to replacethe filter cloths causes significant losses in productivity, as thefilter press cannot be used during the replacement process.

Furthermore, the duplex-type of filter cloths used in the prior art canbe expensive, as both layers of a duplex filter cloth must be removedand replaced when a hole forms in only one of the layers. The process ofassembling the duplex filter cloths on a flanged tube for attachment toa filter plate is also complex and unwieldy.

It is thus desirable to find a new method for securely joining afiltering material such as a cloth fabric or synthetic material, ascommonly used in filtering applications, to a filter plate.

SUMMARY OF THE INVENTION

The present invention addresses the need for an efficient and effectivemethod for attaching a filter cloth to a filter plate installed in afilter press. In an illustrative embodiment of the present invention, aflanged cloth connector ring is fastened about the inner edge of acentral feed port in a filter cloth to attach the filter cloth to afilter plate. The connector ring may include a collar portion and aflanged tab portion extending substantially perpendicular to the collarportion. The filter cloth is attached to the connector ring at thecollar portion. The flanged tab portion includes a tab clip on an outersurface thereof configured to interface with a slot or bore in thefilter plate body, thereby connecting the filter cloth to a first sideof the filter plate. A locking ring or a distribution ring may be usedto retain the connector ring and lock the tab clip into the filter platebody. Serrations may be provided on an inner surface of the tab portionof the connector ring to hold the lock ring or distribution ring inplace by friction fit.

An assembled filter plate may comprise a pair of filter cloths, whichare individually attached to each side of the plate using the clothconnector ring and a locking or distribution ring. The cloth connectorring may individually connect each filter cloth, or a tube-shaped clothconnector ring may include flanged tab portions having tab clips onopposite ends of the tube to connect two filter cloths on either side ofthe filter plate.

The cloth connector ring may include a cloth seat on an outer surface ofthe collar portion for seating an edge of a filter cloth, such that thefilter cloth is substantially flush with a radially inner flange of thecollar portion.

The filter cloths in the filter press may suffer damage due to thefilling velocity of the liquid in the filter press and the abrasivequality of the slurry. To prevent such abrasion damage, in exemplaryembodiments, the filter cloths may have one or more reinforcement unitsattached to the filter cloths. A reinforcement unit is a piece of areinforcement material, e.g. a type of plastic, attached to a part of afilter cloth to protect that part of the filter cloth from abrasion. Inan exemplary embodiment, a donut-shaped reinforcement unit is attachedsymmetrically around the feed hole of the filter cloth. When the filtercloth is assembled between a filter plate and a distribution ring, aninner radial portion of the reinforcement unit lies underneath thedistribution ring and an outer radial portion of the reinforcement unitextends beyond the distribution ring. That is, the distribution ringseats on top of the reinforcement unit attached to the filter cloth suchthat the reinforcement unit extends beyond the face of the distributionring.

According to one aspect, the invention features a filter cloth assemblyhaving a liquid permeable filtering media attached to a connector ring.The liquid permeable filtering media separates at least one solid fromat least one liquid in a slurry. The filtering media has a feed holeformed therein that allows passage of a slurry through the filter cloth.The connector ring includes a flange having an upper flange section anda lower flange section. The lower flange section receives an edge of thefeed hole to connect the filtering media to the connector ring such thatthe face of the filtering media is substantially flush with the upperflange section.

In another aspect, the invention features a connector for attaching afilter cloth to a filter plate in a filter press. The connector ringincludes a collar portion and a tab portion. The collar portion has anupper collar section and a lower collar section. The lower collarsection couples to the perimeter of a central opening of the filtercloth and seats a face of the filter cloth substantially flush with theupper collar section. The tab portion extends at an angle relative tothe collar portion configured to engage a recess in the filter plate.

In yet another aspect, the invention features a method of assembling afilter cloth. The method includes providing a connector ring having aflange that includes an upper flange section and a lower flange sectionand positioning a bonding agent mixed with a metal powder in the lowerflange section. The lower flange section receives an edge of a liquidpermeable filtering media. The method also includes locating an edge ofthe filtering media in the lower flange section and heating by inductionthe metal powder to bond and fixedly retain the filtering media in thelower flange section such that the filtering media is substantiallyflush with the upper flange section

In still another aspect, the invention features a method of assembling afilter plate. The method includes attaching a first filter clothcomprising a filter media and a central opening to a connector ring andengaging the tab portion of the connector ring with a recess in thefilter plate. The connector ring includes a collar portion and a tabportion extending perpendicular to the collar portion. The collarportion has an upper collar portion and a lower collar portion. Thelower collar portion attaches to the first filter cloth such that thefirst filet cloth is substantially flush with the upper collar portionof the connector ring. The filter plate includes a feed port forproviding a slurry to be filtered.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following description and from theaccompanying drawings, in which like reference characters refer to thesame parts throughout the different views. The drawings illustrateprinciples of the invention and, although not to scale, show relativedimensions.

FIG. 1 illustrates a filter press suitable for implementing anillustrative embodiment of the invention.

FIG. 2 is a cross-sectional view of a filter plate stack of the filterpress of FIG. 1.

FIG. 3 shows a filter plate in the filter press of FIG. 1, in accordancewith an illustrative embodiment of the present invention.

FIG. 4 is a cross-sectional view of a central portion of an assembledfilter plate according to an illustrative embodiment of the invention.

FIG. 5 is a top view of the portion of the filter plate shown in FIG. 4.

FIG. 6 is an exploded cross-sectional view of the portion of the filterplate of FIG. 4.

FIG. 7 is a detailed cross-sectional view of the cloth seal connectorring of FIG. 4.

FIG. 8 is a cross-sectional view of a central portion of an assembledfilter plate according to another embodiment of the invention.

FIG. 9 is a top view of the portion of the filter plate shown in FIG. 8.

FIG. 10 is an exploded cross-sectional view of the portion of the filterplate of FIG. 8.

FIG. 11 is a cross-sectional view of a central portion of an assembledfilter plate stack according to another embodiment of the invention,including a plurality of distribution rings.

FIG. 12 is a detailed cross-sectional view of an embodiment of a clothseal connector ring constructed according to principles of theinvention.

FIG. 13 is a detailed cross-sectional view of the cloth seal connectorring after attachment of the filter cloth.

FIG. 14 is a cross-sectional view of a central portion of an assembledfilter plate according to an illustrative embodiment of the invention.

FIG. 15 is a detailed cross-sectional view of an embodiment of a clothseal connector ring constructed according to principles of theinvention.

FIG. 16 is a detailed cross-sectional view of the cloth seal connectorring after attachment of the filter cloth.

FIG. 17 is a top view of the portion of the filter plate shown in FIGS.15 and 16.

FIG. 18A is a perspective view of a portion of an exemplary filterplate, a portion of an exemplary reinforced filter cloth, and adistribution ring.

FIG. 18B is a perspective view of the filter plate, filter cloth, anddistribution ring shown in FIG. 18A assembled together.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the illustrative embodiments, the present invention provides animproved system and method for attaching one or more filter cloths to afilter plate in a filter press. The illustrative system includes a clothconnector ring, which connects a filter cloth with a filter plate. Thecloth connector ring facilitates assembly of a filter plate, is designedfor manufacturability, is low in cost and provides improved efficiencyand productivity of a filter press implementing the cloth connector ringto attach a filter cloth to a filter plate. The present invention willbe described below relative to illustrative embodiments. Those skilledin the art will appreciate that the present invention may be implementedin a number of different applications and embodiments and is notspecifically limited in its application to the particular embodimentsdepicted herein.

FIG. 1 illustrates a filter press 10 suitable for implementing anillustrative embodiment of the invention. The illustrative filter press10 is a batch filtering machine comprising a plurality of filter plates20 clamped together and sealed against each other on the wedge sides toform a filter plate stack 12. The filter plates form filter chambers 23between each other. The filter plates support and are covered by filtercloths to form multiple cavities between the plates for collectingsolids. The filter press 10 includes a feed head 18 at a first end ofthe machine containing piping for delivering a slurry to be filtered. Asused herein, “slurry” refers to a mixture of liquid and solids that isintroduced to a filter press for separation. At a second end of thefilter press 10 is a crosshead 14 containing a clamping mechanism. Amoving plate 16, known in the art as a “tail plate”, clamps the filterplate pack. During a filtering operation, slurry is pumped into filterchambers formed by the stacked filter plates and filter cloths, and ispushed against a filter cloth on a proximate filter plate. Liquid(filtrate) from the slurry passes through the filter cloth and exitsthrough filtrate ports in a filter plate. Solids from the slurry collecton the surface of the filter cloth within the chamber until the chamberis full, which forms a filter cake. The filter cake may be washed orblown dry, if necessary. The collected filter cakes are discharged,completing the filtration cycle.

FIG. 2 is a cross-sectional view of a filter plate stack 12 of thefilter press of FIG. 1, which comprises a plurality of filter plates 20stacked together. An embodiment of an individual filter plate 20 isshown in FIG. 3. As shown, each filter plate 20 may comprise a frame 23with a first layer or sheet of filtering cloth 22 and a second layer orsheet of filtering cloth 24 sealably joined to opposite sides of theframe 23. The filtering cloths 22, 24 form cavities or chambers 21between the filter plates 20 for retaining solids between the filteringcloths 22, 24 when two or more filter plates 20 are stacked together. Aslurry feed port 40 is formed in the center of the filter plate 20 fordelivering a slurry to be filtered. Filtrate ports 25 may be provided atthe edges of the frame 23 for receiving and transferring filtrate fromthe filter plate 20. In the illustrative embodiment, stay busses 26, orother suitable stabilization devices, may be provided around the centralfeed port 40 to help stabilize the filtrate plate 20. One skilled in theart will recognize that the invention is not limited to the illustratedfilter plate stack or filter plate configuration, and that the filterplate stack and filter plate may have any suitable configuration forfiltering a slurry.

The filter cloths 22 and 24 may be fabricated from a natural or man-madematerial or any combination thereof, which is acceptable for filteringapplications. Suitable fabrics for forming the filter cloths 22, 24include, but are not limited to natural fibers, such as cotton, orplastic fibers, such as polypropylene or nylon, for retaining cakesolids. One skilled in the art will recognize that any suitable materialfor filtering a slurry may be used.

During a filtering process, a filter cloth 22 or 24 covers each side ofthe filter plate 20. As the slurry is pumped into the plate stack 12,the filter cloths retain the solids and allow the filtrate to passthrough, completing the separation process. The filter cloths 22, 24 arefastened together and attached at an outside edge 27 formed in theperimeter of the plate 20. Any suitable means known in the art may beused to form the peripheral seal, including, but not limited to Velcro,ties, o-rings, a rope hammered into a groove extending along theperimeter, and so on. The filter cloths 22, 24 are sealingly connectedto each side of the filter plate 20 at the feed position 40, whichreceives a pumped slurry under pressure to fill the filter chamber 21.

According to an illustrative embodiment of the invention, each filtercloths 22 or 24 is connected to a side of a filter plate using a clothconnector ring. According to the illustrative embodiment, the filterplate includes a surface having a recess or other feature configured toreceive and retain a cloth connector ring for attaching a filter clothto the filter plate. For example, as described with respect to FIGS.4-11, a flanged connector ring 42, 44, 92, 94, 212 or 214 may be used tosealingly connect a filter cloth to a filter plate at a feed position 40of the filter plate. According to the illustrative embodiment, the feedposition 40 is located in the center of the plate. One skilled in theart will recognize that the feed position, and thus the attachment pointof the filter cloths 22, 24 may alternatively be located in a corner orlocation offset from the center of the filter plate 20.

FIG. 4 is a cross-sectional side view of an assembled filter plate 20 atthe point of attachment of the filter cloths 22, 24 according to anillustrative embodiment of the invention. FIG. 5 is a detailed top viewof the region of the filter plate 20 where a filter cloth 22 is attachedto the filter plate. FIG. 6 is an exploded cross-sectional view of thecomponents of the filter plate shown in FIG. 4. In the illustrativeembodiment, each filter cloth 22, 24 includes a feed hole 52, 54,respectively, corresponding to the slurry feed port 40 of the filterplate. In the illustrative embodiment, a feed hole is located in thecentral portion of the filter cloth, though one skilled in the art willrecognize that the feed hole and feed ports may be located in anysuitable position. A first cloth connector ring 42 is connected to thefirst filter cloth 22 around the perimeter of the feed hole 52 forattaching to first filter cloth 22 to a first side of the filter plate20. A second cloth connector ring 44 is connected to the second filtercloth 24 around the perimeter of the feed hole 54 for attaching thesecond filter cloth 24 to a second side of the filter plate 20.According to the illustrative embodiment, the cloth connector rings 42,44 may be connected to the corresponding filter cloth by sewing, weldingor mechanically coupling an inner edge of the filter cloth, defined bythe central hole 52 or 54, to the corresponding connector ring 42 or 44through means known in the art. One skilled in the art will recognizethat any suitable means for connecting a connector ring to a filtercloth may be used in accordance with the teachings of the invention.

The cloth connector ring may have any suitable configuration. Forexample, the cloth connector ring may have a circular cross-section, apolygonal cross-section or have any suitable shape, preferably matchingthe shape of the feed hole 52 of the filter cloth to which the clothconnector ring is attached.

According to an illustrative embodiment, as shown in FIGS. 4-7, theslurry feed port 40 of the filter plate 20 is configured to receive andretain a cloth connector ring 42 or 44. As shown, a filter cloth 22 or24 may be attached to a side of the filter plate 20 by inserting anassociated cloth connector ring 42 or 44 in the feed port 40, such thatthe inner surface of the feed port 40 receives and retains the clothconnector ring, thereby attaching a filter cloth associated with thecloth connector ring to the filter plate. According to the illustrativeembodiment, the cloth connector rings are configured to be received andretained by the inner surface of the central slurry feed port. Forexample, the cloth connector rings may have an outer surface that iscomplementary to the inner surface of the central slurry feed port. Oneskilled in the art will recognize that the filter plate 20 and the clothconnector rings may have any suitable configuration for coupling thecloth connector ring to the filter plate, and that the invention is notlimited to the illustrated configuration.

In the embodiment shown in FIGS. 4 and 6, the slurry feed port 40 of theillustrative filter plate 20 includes recesses or grooves, illustratedas first and second undercut counter bores 46, 47 or slots cut into thefilter plate on the inner surface of the port 40. In the illustrativeembodiment, the bores 46, 47 extend in a radial direction, perpendicularto the longitudinal axis -A- of the filter plate 20. Each of the bores46, 47 defines a shoulder and a radial groove formed in the counter boreadjacent to the shoulder. The first undercut counter bore 46 receivesthe first cloth connector ring 42 attached to the first filter cloth 22and the second undercut counter bore 47 receives the second clothconnector ring 44 attached to the second filter cloth 24. The innersurface of the central feed port 40 also includes a first inclinedsurface 466 extending from the first side of the filter plate inward tothe first bore 46 at an incline relative to the longitudinal axis -A-and a second inclined surface 467 extending from the second side of thefilter plate 20 inward toward the second bore 47. One skilled in the artwill recognize that the surfaces 466 and 467 may alternatively extendparallel to the axis -A-. An annular central protrusion 468 extendsaround the inner surface of the feed port 40 between the bores 46, 47.The annular central protrusion 468 is defined by walls 46 c and 47 c ofthe bores 46 and 47, respectively, and an axially extending surface 468a having a reduced diameter relative to the bores 46 and 47 and thesurfaces 466 and 467.

Locking rings 62, 64 may also be provided for locking the cloth sealring connector rings 42, 44, respectively in place after insertion,thereby locking the filter cloths 22, 24 to the filter plate 20.

FIG. 7 illustrates an embodiment of a cloth connector ring 42 in detail,though one skilled in the art will recognize that the cloth connectorring 42 may have any suitable configuration for coupling to the filterplate 20 to attach a filter cloth to thereto. As shown in FIG. 7, theillustrative cloth connector ring has a configuration that iscomplementary in shape to the feed port inner surface, comprised ofsurfaces 466, 467, 468 a and bores 46 and 47. As shown, the clothconnector ring 42 comprise a flat, preferably annular, collar portion421 attaching the cloth connector ring to a filter cloth. The collarportion 421 is configured to abut a first side of the filter plate inthe vicinity of the feed port 40, as shown in FIG. 4.

The cloth connector ring 42 further includes a flanged tab clip portion422 extending inward and substantially perpendicular to the collarportion 421. The flanged tab portion 422 is configured to abut the innersurface of the central feed port 40 to secure the cloth seal connectorring 42, and thus a connected filter cloth, to the filter plate. The tabportion 421 terminates in an axially outward extending tab clip 424,which is received by the bore 46 of the filter plate to secure theconnector ring 42 to the filter plate. The illustrative tab clip flange424 includes a first surface 424 a configured to abut a axiallyextending wall 46 a of the bore and a second surface 424 b configured toabut a longitudinally extending wall 46 b of the bore. A third wall 424c and a fourth wall 424 d of the flange 424 extend at inclines relativeto the longitudinal axis and converge at an end, illustrated as a point424 e forming the end of the connector ring 42. The point 424 e abuts asecond axially extending wall 46 c, which terminates in the protrusion468. Alternatively, the third wall 424 c and fourth wall 424 d may forma flat end configured to abut, and lie flat against, the centralprotrusion 468. One skilled in the art will recognize that the tabportion 422 may have any suitable configuration for cooperating with asurface of the filter plate to attach the connector ring to the filterplate.

The illustrative tab portion 422 may further include serrations 423 onan inner face 425 of the tab portion 422, opposite the surfaces thatinteract with the feed port inner surface. The serrations 423 enhancethe friction fit between the connector ring and a corresponding lockingring 62 or a distribution ring (described below). As shown, the tabportion outer surface 426 matches the inclined surface 466 of the slurryfeed port 40 of the filter plate and is configured to abut against theinclined surface 466. As shown, the tab portion outer surface 426 isinclined relative to the longitudinal axis at a similar angle to theangle of the inclined surface 466. The tab portion outer surface 426abuts the inclined surface 466 of the slurry feed port 40 when thefilter plate is assembled to securely and sealingly connect the filtercloth 22 to the filter plate 20. One skilled in the art will recognizethat the tab portion outer surface 426 and the inner surface 466 of theslurry feed port may have any suitable configuration. According to apreferred embodiment, the tab portion outer surface 426 and the innersurface 466 of the slurry feed port have complementary shapes tofacilitate attachment of the cloth connector ring to the filter plate.

According to the illustrative embodiment, the second cloth connectorring 44 of FIGS. 4-6 is configured similar to the first cloth connectorring 42, though one skilled in the art will recognize that the clothconnector rings 42 and 44 may have different configurations. One skilledin the art will recognize that the tab portions and cloth connectorrings are not limited to the illustrative configuration and that anysuitable configuration for sealingly connecting the filter cloth to thefilter plate may be used in accordance with the invention.

The cloth connector ring 42, 44 may be manufactured from rubber,thermoplastic rubber, plastic, cloth, nylon, polypropylene, polyester orany other suitable material and may be formed by machining, molding orany other suitable process.

To assemble the filter plate 20 of FIGS. 4-6 using a cloth connectorring having a configuration shown in FIG. 7, a first filter cloth 22 isconnected to a first cloth connector ring 42 and aligned with the filterplate, such that the feed port 52 of the filter cloth 22 aligns with thefeed port 40 of the filter plate 20. The tab portion 422 of theconnector ring is pushed into the feed port 40, such that the flange 424engages the bore 46 and the inclined outer surface 426 abuts theinclined inner surface 466 of the filter plate. Next, the locking ring62 is pushed into position in the central feed port 40 to lock the tabclip flange 424 into the bore 46 on the filter plate body. The lockingring is pushed until the end of the locking ring abuts the protrusion468 and the outer surface of the locking ring abuts the inner surface ofthe tab portion. The locking ring 62 is stopped by the protrusion ring468 and held in place by friction fit with the serrations 423 and theprotrusion ring 468. The outer edges of the filter cloth are thenattached to the outer edges of the filter plate frame through meansknown in the art, as described above. The second filter cloth 24 isattached to the second side of the filter plate 20 in a similar manner,using the second cloth connector ring 44 and second locking ring 64.

According to another embodiment of the invention, the recesses receivingthe connector rings for attaching a filter cloth to a filter platecomprise slots. For example, as shown in FIGS. 8-10, a filter plate 70includes a first slot 86 for attaching a first filter cloth 72 to afirst side of the filter plate 70 using a first cloth connector ring 92and a second slot 88 for attaching a second filter cloth 72 to a secondside of the filter plate 70 using a second cloth connector ring 94. Asshown, in the second embodiment, the central feed port 90 has a straightinner surface 91. The first slot 86, which preferably comprises anannular undercut groove, is spaced axially outwardly from andsurrounding the central feed port 90 and is cut into the first side ofthe filter plate for receiving the first connector ring 92 and firstlock ring 96 in order to fasten the first filter cloth 72 to the filterplate 70. A second slot 88, preferably an annular undercut groovealigned with the first circular undercut slot and spaced axiallyoutwardly from and surrounding the central feed port 90, is cut into thesecond side of the filter plate for receiving the second connector ring94 and second lock ring 98 in order to fasten the second filter cloth 74to the filter plate 70.

According to the illustrative embodiment, the filter cloths 72, 74 andconnector rings 92, 94 of FIGS. 8-10 are substantially identical to thefilter cloths 22, 24 and connector rings 42, 44 of FIGS. 4-7. However,in the embodiment of FIGS. 8-10, the diameters of the feed holes 82, 84of the filter cloths and connector rings is larger than the diameter ofthe central feed port 90, rather than the same as the diameter of thecentral feed hole, as shown in the embodiment of FIGS. 4-7. In theembodiment of FIGS. 8-10, the diameter of the connector rings and filtercloths are configured to allow insertion of the tab portions 922, 942 ofthe connector rings 92, 94 in the slots 86, 88 of the filter plate.

As shown, each slot 86, 88 is spaced from the feed port 90 and includesa main portion 861, 881, respectively, extending substantially parallelto the longitudinal axis. The main portions 861, 881 have an inclinedwall 861 a, 881 a, respectively, configured to abut the inclined wall866, 868 of the corresponding tab portion 922, 942, respectively and alongitudinally extending wall 861 b, 881 b. Each slot further includes aradially extending recess 926, 928, respectively for receiving theflange 924, 925 of the tab portion on the connector ring.

To assemble the filter plate 70 of FIGS. 8-10, the first filter cloth 72is connected to the associated cloth connector ring 92 and aligned withthe filter plate such that the feed port of the filter cloth aligns withthe feed port of the filter plate. The tab portion 922 of the connectorring is pushed into the circular slot 86, such that the flange 924engages the radially extending recess 926 and the inclined inner surface866 abuts the inclined inner surface 861 a of the filter plate. Next,the locking ring 62 is inserted into the slot 86 between the tab portion922 and the longitudinally extending wall 861 b and pushed into positionto lock the tab clip flange 924 into the bore 46 on the filter platebody. The locking ring 96 is pushed until the end of the locking ringabuts the radially extending wall of the recess 926. The serrations onthe surface of the connector ring hold the locking ring in place byfriction fit. The second filter cloth 74 is attached to the second sideof the filter plate 70 in a similar manner, using the second clothconnector ring 94 and second locking ring 98.

According to yet another embodiment of the invention, shown in FIG. 11,a filter plate pack 100 includes one or more distribution rings 110 inplace of the lock ring to secure the cloth connector rings and filtercloths to the filter plate frame. Distribution rings are known in theart and are used in filter presses to support the filter plate at thefeed port to prevent overflexing the plate during the feed cycle, causedby pressure differentials. The distribution rings 110 ensure that theplates are stacked evenly to enhance the filtering process. Eachdistribution ring contacts a distribution ring on an adjoining plate toform a continuous support along the length of a filter plate pack.Slurry enters a filter chamber 120 between the filter plates viaperipheral slots formed or machined into the circumference of thedistribution rings faces. Slurry also enters a filter chamber 120through one or more channels 180 formed within the distribution rings110.

As shown in FIG. 11, each filter plate 200 has a pair of filter cloths202, 204 attached to either side of the filter plate via connector rings212, 214. The connector rings are attached to the filter cloths at thecentral opening of each feed cloth, though one skilled in the art willrecognize that the connector rings may be attached to any suitablelocation on the filter plate using any suitable connection means. In theillustrative embodiment, the connector rings 212, 214 engage counterbores 146, 147 in the inner surface of the central feed port 190 of thefilter plate, as described above with respect to the embodiments shownin FIGS. 4-7, though one skilled in the art will recognize that theinvention is not limited to the illustrated embodiment. A distributionring 110 is pushed into position and held by a press fit between aconnector ring and an adjacent distribution ring. A distribution ring100 is also held by friction of the tab serrations on the tab portion ofthe connector rings 212, 214. By the action of clamping the filterpress, the distribution rings 110 are correctly seated withoutcontacting the bottom of the counter bores 146, 147 of the filter plate.When the filter is clamped, a positive seal is created between thedistribution ring and the cloth connector ring.

The filter cloths 202, 204 in the filter press may suffer damage due tothe filling velocity of the liquid in the filter press and the abrasivequality of the slurry. To protect the filter cloths from abrasiondamage, exemplary embodiments provide one or more reinforcement unitsattached to the filter cloths 202, 204. A reinforcement unit is a pieceof a reinforcement material, e.g. a type of plastic, attached to a partof a filter cloth to protect that part of the filter cloth fromabrasion.

FIG. 18A is a perspective view of a portion of an exemplary filter plate1612, a portion of an exemplary reinforced filter cloth 1600, and adistribution ring 1616. In the exemplary embodiment shown in FIG. 18A, adonut-shaped reinforcement unit 1608 is attached to the filter cloth1600 symmetrically around the feed hole 1604 of the filter cloth 1600.FIG. 18B is a perspective view of the filter plate 1612, filter cloth1600, and distribution ring 1616 shown in FIG. 18A assembled together.As shown in FIG. 18B, when the filter cloth 1600 is assembled between afilter plate 1612 and a distribution ring 1616, an inner radial portionof the reinforcement unit 1608 lies underneath the distribution ring1616, and an outer radial portion of the reinforcement unit 1608 extendsbeyond the distribution ring 1616. That is, the distribution ring 1616seats on top of the reinforcement unit 1608 attached to the filter cloth1600, such that the reinforcement unit 1608 extends beyond the face ofthe distribution ring 1616.

The filter plate 200 of FIG. 11 is substantially identical to filterplate of FIGS. 4-7, however, the counter bores 146, 147 of the plate 200may be wider than the bores 46, 47 of the plate 20 to prevent thedistribution rings 110 from contacting the wall of the protrusion 1468in filter plate 200.

In addition to facilitating installation of the filter cloths 202, 204on a filter plate 200, the embodiment of FIG. 11 facilitatesinstallation of the distribution rings 110 in the filter stack 100.Prior distribution rings are generally awkward to install and arerequired to be screwed together. The present invention allows manualinstalling without difficulty. The distribution rings can be insertedinto the feed ports by hand and are held in place by friction fit.

FIGS. 12-14 depict another embodiment of a cloth connector ring suitablefor connecting a filter cloth to a filter plate according to theteachings of the invention. FIG. 12 illustrates another embodiment of acloth connector ring 1200 in detail prior to connecting a filter cloth22 to the connector ring 1200. FIG. 13 depicts an embodiment of a clothconnector ring 1200 in detail after connecting the filter cloth 22 tothe connector ring 1200. FIG. 14 is a cross-sectional side view of anassembled filter plate 20 at the point of attachment of the filtercloths 22, 24 according to an illustrative embodiment of the invention.

As shown in FIG. 12, the illustrative cloth connector ring has aconfiguration that is complementary in shape to the feed port innersurface of the filter plate 20. As shown, the cloth connector ring 1200comprise a flat, preferably annular, collar portion 1204 attaching thecloth connector ring to a filter cloth. The collar portion 1204 isconfigured to abut a first side of the filter plate in the vicinity ofthe feed port 40, as shown in FIG. 14. The collar portion 1204 forms afilter cloth seat on an outer surface for receiving an edge of a filtercloth, and includes an upper collar section 1205, a lower collar section1206, and an end nub 1207. The upper collar section 1205 is preferablyformed at a radially inner section of the cloth connector ring 1200around central opening 1252 functions as a stop or catch for the filtercloth 22 when the filter cloth 22 is attached to the connector ring1200.

The lower collar section 1206 is configured to receive a bonding agent120 a and the filter cloth 22 to attach the filter cloth 22 to theconnector ring 1200. The lower collar section 1206 functions as a filtercloth seat such the filter cloth 22 is substantially flush with theupper collar section 1205 once attached. Seating the filter cloth 22substantially flush with the upper collar section 1205 is advantageous,because during scraping of the filter cloth 22, the scraper is lesslikely to cause a separation of the filter cloth 22 and the connectorring 1200.

The end nub 1207 protrudes from an end of the collar portion 1204. Theend nub can protrude substantially perpendicular from the end of thecollar portion 1204. It should be understood that the end nub 1207 canextend at other angles as well. The end nub 1207 is constructed of thesame material as the collar portion 1204 and mixes with the bondingagent 120 a during the attachment process (e.g., heating by radiofrequency or other means).

The bonding agent 120 a can be shaped as an annular ring, although othershapes are contemplated. An exemplary bonding agent is a thermoplasticbonding agent, such as polypropylene, mixed with a ferrous metal powder.The proportion of metal powder used can be between 1% and 50% by volumeof the bonding agent. It should be understood that other bonding agentscan be as well.

The cloth connector ring 1200 further includes a flanged tab clipportion 1208 extending inward and substantially perpendicular to thecollar portion 1204. The flanged tab portion 1208 is configured to abutthe inner surface of the central feed port 40 to secure the cloth sealconnector ring 1200, and thus a connected filter cloth, to the filterplate. The tab portion 1208 terminates in an axially outward extendingtab clip flange 1209, which is received by the bore 46 of the filterplate to secure the connector ring 1200 to the filter plate. Theillustrative tab clip flange 1209 is semicircular in shape. One skilledin the art will recognize that the tab portion 1208 may have anysuitable configuration for cooperating with a surface of the filterplate to attach the connector ring to the filter plate. For example, thetab portion can be shaped similar to that shown and described in FIG. 4.The illustrative tab portion 1208 may further include serrations 1212 onan inner face 1216 of the tab portion 1208, opposite the surfaces thatinteract with the feed port inner surface.

FIG. 13 shows the configuration of the connector ring 1200 after theconnection of the filter cloth 22. As shown, the bonding agent 120 a andthe end nub 1207 are heated to cause the mixing thereof. Examples ofheating can include but are not limited to induction heating, forced airheating, radio frequency heating, microwave heating, and the like. As aresult, the mixed bonding agent and end nub material attach the filtercloth 22 to the connector ring 1200 such that an outer face of thefilter cloth 22 is substantially flush with the upper collar section1205.

FIG. 14 shows two connector rings connected to the filter plate 20 in amanner similar to that previously described. As shown, a second clothconnector ring 1200′ is configured similar to the first cloth connectorring 1200, though one skilled in the art will recognize that the clothconnector rings 1200′ and 1200 may have different configurations. Oneskilled in the art will recognize that the tab portions and clothconnector rings are not limited to the illustrative configuration andthat any suitable configuration for sealingly connecting the filtercloth to the filter plate may be used in accordance with the invention.As shown in FIGS. 12-14, the tab portion outer surface 1210 matches theinclined surface 466 of the slurry feed port 40 of the filter plate andis configured to abut against the inclined surface 466. As shown, thetab portion outer surface 1210 is inclined relative to the longitudinalaxis at a similar angle to the angle of the inclined surface 466. Thetab portion outer surface 1210 abuts the inclined surface 466 of theslurry feed port 40 when the filter plate is assembled to securely andsealingly connect the filter cloth 22 to the filter plate 20. Oneskilled in the art will recognize that the tab portion outer surface1210 and the inner surface 466 of the slurry feed port may have anysuitable configuration. According to a preferred embodiment, the tabportion outer surface 1210 and the inner surface 466 of the slurry feedport have complementary shapes to facilitate attachment of the clothconnector ring to the filter plate.

Locking rings 162, 164 may also be provided for locking the clothconnector rings 1200, 1200′, respectively in place after insertion,thereby locking the filter cloths 22 to the filter plate 20. As shown inFIG. 14, each locking ring may have a radially outer surface that isconfigured to abut the serrated surface 1212 of the corresponding filtercloth connector ring. The radially outer surface of the locking ring maybe serrated, as shown in FIG. 14, or have another suitableconfiguration.

According to another embodiment of the invention, the two clothconnector rings 1200 and 1200′ may be connected to each other to form aunitary structure for connecting a plurality of filter cloths toopposite sides of a filter plate 20.

FIGS. 15-17 show another embodiment of a cloth connector ring suitablefor connecting a filter cloth to a filter plate according to theteachings of the invention. FIG. 15 illustrates another embodiment of acloth connector ring in detail prior to connecting the filter cloth 22to the connector ring. FIG. 16 depicts an embodiment of a clothconnector ring in detail after connecting the filter cloth 22 to theconnector ring. FIG. 17 is a top view of the region of the filter plate20 where a filter cloth 22 is attached to the filter plate, according toan illustrative embodiment of the invention.

With reference to FIG. 15, the cloth connector ring may comprise arubber or like component forming a tube 1504 that is attached to twofilter cloths 22A, 22B. The tube 1504 has radially extending flanges1508 at each end of the tube 1504. Each flange 1508 includes an radiallyinner section 1512 and a radially outer section 1516. The radially innersection 1512 functions as a stop or catch for the feed hole of thefilter cloth 22 when the filter cloth 22 is attached to tube 1504.

The radially outer section 1516 is configured to receive a bonding agent1520 and the filter cloth 22 to attach the filter cloth 22 to the tube1504. The radially outer section 1516 functions as a “seat” such thatthe filter cloth 22 is substantially flush with the radially innersection 1512 once attached, as shown in FIG. 16. Seating the filtercloth 22 substantially flush with the radially inner section 1512 isadvantageous, because during scraping of the filter cloth 22, thescraper is less likely to cause a separation of the filter cloth 22 andthe tube 1504.

An annular piece of bonding agent 1520, 1524 is located between each ofthe flanges 1508 and the filter cloths 22. The bonding agent 1520, 1524can also have other shapes. An exemplary bonding agent is athermoplastic bonding agent mixed with a ferrous metal powder. Theproportion of metal powder used can be between 1% and 50% by volume ofthe bonding agent. It should be understood that other bonding agents canbe as well.

FIG. 16 shows the configuration of the tube 1504 after the connection ofthe filter cloth 22. As shown, the bonding agent 1520, 1524 is heated tocause the filter cloth to be attached to the radially outer section1516. Example of heating can include but are not limited to inductionheating, forced air heating, radio frequency heating, microwave heating,and the like. After heating the filter cloth 22 is attached to the tube1504 such that an outer face of the filter cloth 22 is substantiallyflush with the radially inner section 1512.

As shown in the detailed top view of FIG. 17, the filter cloth 22 abutsthe radially inner section 1512. Also, the outer face of the filtercloth 22 rests substantially flush with the radially inner section 1512.

According to an alternate embodiment, the tube 1504 forming the clothconnector ring with radially inner section and the radially outersection 1512 and 1516, respectively, may comprise two separatecomponents, each having an radially inner section 1512 and radiallyouter section 1516 to form a filter cloth seat on an outer surfacethereof, to allow for independent attachment of a filter cloth to afilter plate.

The illustrative systems and methods for attaching filter cloths to afilter plate using a flanged cloth connector ring provides significantadvantages over the prior art. The present invention allows a pair offilter cloths to be individually and independently installed on oppositeside of a filter without requiring the filter cloths to be attached toeach other. In this manner, one filter cloth can be removed and replacedwithout having to remove and replace the associated filter cloth,resulting in significant cost savings. The illustrative system is simpleto manufacture and provides easy and fast installation of a filter clothon a filter plate. Furthermore, the illustrative filter plate assemblyallows for a central feed design, which has enhanced feed delivery overa corner feed design.

It is thus seen that the invention efficiently attains the objects setforth above, among those made apparent from the preceding description.Since certain changes may be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are to cover allgeneric and specific features of the invention described herein, and allstatements of the scope of the invention which, as a matter of language,might be said to fall therebetween.

Having described the invention, what is claimed as new and desired to besecured by Letters Patent is:
 1. A filter assembly, comprising: a filterplate having an axially outer surface and a feed hole extending axiallyinto the axially outer surface, the feed hole including a counter borethat defines a shoulder, and a radial groove formed in the counter boreadjacent to the shoulder; a liquid permeable filtering media having anaxially inner surface abutting the axially outer surface of the filterplate for separating at least one solid from at least one liquid in aslurry, the filtering media having a feed hole formed therein that iscoaxially aligned with the feed hole in the filter plate for allowingpassage of a slurry into a filter chamber defined by an axially outersurface of the filtering media; a connector ring comprising a flangehaving flange radially inner section and a radially outer section, theradially inner section configured to receive an edge of the feed hole ofthe filtering media and the radially outer section being configured toreceive an annular portion of the axially inner surface of the filteringmedia that surrounds the feed hole to connect the filtering media to theconnector ring, wherein an annular portion of the axially outer surfaceof the filtering media adjacent the filtering media feed hole issubstantially flush with an axially outer surface of the radially innersection of the connector ring, wherein the connector ring engages theradial groove in the filter plate feed hole to connect the connectorring to the filter plate; and a distribution ring to secure thefiltering media and the connector ring to the filter plate, wherein thedistribution ring includes a cylindrical portion having a radially outersurface that abuts a radially inner surface of the connector ring, anannular flange extending radially outwardly from an axially outer end ofthe cylindrical portion, the annular flange having an axially innersurface that abuts the axially outer surface of the radially innersection of the connector ring and the annular portion of the axiallyouter surface of the filtering media adjacent the filtering media feedhole, and the cylindrical portion including an annular inner axialsurface that is adjacent to and spaced apart from the shoulder of thecounter bore.
 2. The filter assembly of claim 1, wherein thedistribution ring is held by a press fit between the connector ring andthe distribution ring.
 3. The filter assembly of claim 1, wherein theconnector ring further comprises a tab portion having a plurality ofserrations, extending at an angle relative to the flange, and beingconfigured to engage the groove in the filter plate counter bore, andwherein the plurality of serrations engage the distribution ring toretain the radially outer surface of the distribution ring in the filtercloth assembly.
 4. The filter assembly of claim 1, wherein thedistribution ring supports the connector ring at the feed hole toprevent pressure differentials from overflexing the filter plate.
 5. Thefilter assembly of claim 1, wherein the distribution ring furthercomprises one or more radial slots formed in an axially outer face ofthe annular flange of the distribution ring to allow the slurry to enterthe filter chamber.
 6. The filter assembly of claim 1, wherein theconnector ring further comprises a tab portion extending at an anglerelative to the flange, wherein a radially outer surface of the tabportion engages the feed hole counter bore of the filter plate, andwherein the radially outer surface of the cylindrical portion of thedistribution ring engages a radially inner surface of the tab portion tolock the connector ring into the filter plate.
 7. The filter assembly ofclaim 1, further comprising: a positive seal between the distributionring and the connector ring created by clamping the filter clothassembly.
 8. The filter assembly of claim 1, further comprising: areinforcement unit attached to the filtering media to protect thefiltering media from abrasion damage, a face of the reinforcement unitextending beyond the distribution ring.